Hinge knee preparation instrumentation and associated methods

ABSTRACT

A hinge knee system includes a tibial assembly having a baseplate component and an axle component. The baseplate component has an opening that extends therein from a proximal end toward a distal end thereof. The axle component has a shaft portion receivable within the opening of the baseplate component and an axle connected to the shaft portion that extends in a direction transverse to a longitudinal axis of the shaft portion. The system also includes a femoral assembly that includes a distal femoral component. The distal femoral component includes condylar portions and an intercondylar portion disposed between the condylar portions. The intercondylar portion includes a bearing surface that defines a recess configured to rotatably receive the axle for articulation therewith.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of the filing date of U.S.Provisional Patent Application No. 62/358,222 filed Jul. 5, 2016, thedisclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

Total knee arthroplasty (TKA) or total knee replacement is a commonorthopedic procedure in which damaged or diseased articular cartilageand/or bone of the knee is replaced with a prosthesis. In a TKA, asurgeon generally selects one of several different categories of totalknee prostheses for implantation depending on the needs of the patient.Prior to implantation of such prosthesis, a surgeon generally resects aportion of the patient's native tibia and femur so as to shape thesebones to receive the particular prosthesis selected.

A hinged total knee prosthesis is one category of total knee prostheses.Hinge knee prostheses are typically the most constrained category oftotal knee prostheses as they most significantly limit the total rangeof motion of a patient's repaired knee. However, because of suchconstraint, hinge knee prostheses often provide the most stability andare, therefore, most useful to patients' who have severe jointinstability caused by bone loss, ligament deficiencies, and the like. Inthis regard, hinge knee prostheses are often selected for patientsundergoing a revision procedure in which a previously implantedprosthesis is replaced. This can be due to significant bone loss orligament deficiencies at least partially caused by the previousprosthesis. In addition, hinge knee prostheses are also commonlyselected for patients who have bone cancer, such as osteosarcoma, of thetibia and/or femur.

Performing a revision procedure to implant a hinge knee prosthesis candiffer quite significantly from that of an oncology procedure to do thesame. For example, in a revision procedure, a surgeon removes thepreviously implanted prosthesis exposing bone that had been shaped in aprevious procedure. Although significant deformities can be present, theresected bone and bone deformities often do not extend beyond themetaphysis. So whatever bone stock remains is further shaped andbolstered to receive the hinge knee prosthesis.

In contrast, in an oncology procedure, a patient may have a canceroustumor in the distal femur or proximal tibia. In order to remove suchcancer, a significant portion of the patient's bone is removed alongwith the cancer. In this regard, resection may be performed along thebone's diaphysis thereby removing the entire proximal tibia or distalfemur. In addition, the patient often has a healthy, pristine boneopposite that of the malignant bone. Thus, in order to perform theappropriate replacement, the resected malignant bone must be rebuilt andthe pristine bone must be shaped to receive the appropriate components.

Despite the differences between revision and oncology TKA proceduresthere is some commonality between these procedures in that the tibia andfemur are typically resected first, and then a hinge knee trial isassembled onto the resected bone to assess patellofemoral kinematics andjoint capsule tightness. If adjustments need to be made, the trial isdisassembled and further resections are performed, which may result inan iterative process of assembly, disassembly, and resection that tendsto raise the joint line. In addition, the assembly and disassembly ofthe hinge trial, which often requires an axle to be inserted into afemoral component from a lateral or medial side thereof and through abearing plate disposed between adjacent condylar portions of the femoralcomponent, can be time consuming which can result in increased risk ofinfection and overall recovery time.

Numerous instruments, such as trials, cutting guides, and the like, havebeen made available to help perform hinge knee prosthesis implantationfor both revision and oncology procedures. However, such instrumentsoften differ significantly to account for the differences between theprocedures. Thus, a manufacturer is often required to offer a largeassortment of instrumentation that results in significant manufacturingcosts.

In addition, such instruments are provided to an operating theater insets. Such sets themselves are often comprised of numerous instruments.For example, a currently performed hinge knee procedure may requireabout 24 instrument cases and 28 instrument trays. These instruments maybe stored, cleaned, packaged, and shipped by the manufacturer to thehealthcare facility in which the procedure is to take place. In someinstances, the instruments may be stored and sterilized at thehealthcare facility itself. The demands of manufacturing, storing,maintaining, sterilizing, packaging, shipping and tracking such adiverse, complicated and large quantity of instruments can be expensive,particularly in a world that is increasingly demanding cheaper surgicalprocedures. For example, a set of instruments for performing a TKAprocedure may cost about 40,000 USD to manufacture. These instrumentsmay then be placed into circulation. While in circulation, theseinstruments must be stored, repaired, sterilized, packaged and shippednumerous times over contributing to the overall costs of theinstruments. The more instruments provided in each set, the greater thelife-cycle costs become, which may reflect back to the cost of the TKAprocedure.

Therefore, further improved instruments and consolidation of instrumentsfor use in hinge knee procedures is desired.

BRIEF SUMMARY OF THE INVENTION

Described herein are devices, systems, and methods for performing TKA.In particular, a hinge knee trial assembly is disclosed which can beutilized in revision procedures and oncology procedures to help preparebone for a hinge knee prosthesis. One example of such a hinge kneeprosthesis is disclosed in U.S. application Ser. No. 14/820,151, thedisclosure of which is hereby incorporated herein by reference in itsentirety. The hinge knee trial assembly generally includes a tibialtrial assembly and femoral trial assembly. The tibial trial assemblyincludes an intercondylar axle that can be inserted into anintercondylar space of a femoral component of the femoral trial assemblyand be easily connected thereto for assessment of joint kinematics. Inaddition, the distance between the tibial trial assemblies from thefemoral trial assembly can be adjusted in measured increments while theaxle remains connected to the femoral trial assembly. Furthermore,adjustments of the proximal-distal location of the femoral component ofthe femoral trial assembly can be adjusted relative to the patient'spatella while the hinge knee trial assembly is mounted to the femur andtibia. This allows the joint to be assessed prior to femoral resectionso as to help maintain a natural joint line. In addition to the hingeknee trial assembly, other associated instruments and methods of use arealso described.

In one aspect of the present disclosure, a hinge knee system includes atibial assembly and a femoral assembly. The tibial assembly includes adistal end, a proximal end, and an axle component. The distal end isconfigured to connect to an end of a tibia. The proximal end has aproximally facing bearing surface. The axle component extends from theproximal end and has an axle and axle support. The femoral assemblyincludes a distal femoral component, the distal femoral componentincludes first and second condylar portions and an intercondylar portiondisposed therebetween. The intercondylar portion has a recess configuredto receive the axle and is defined by one or more contoured surfacesthat are configured to articulate with the axle when the axle isreceived within the recess so that the tibial assembly can be rotatedrelative to the femoral assembly about the axle.

Additionally, the tibial assembly may include a proximal tibialcomponent having a diaphyseal portion. The distal end of the tibialassembly may be at a distal end of the diaphyseal portion and may beconfigured to connect to a tibia that has been resected along adiaphysis thereof. The tibial assembly may further include a modulartibial insert that defines the proximally facing bearing surface. Theproximal tibial component may include a tray portion that receives thetibial insert. Also, the axle component may include a boss slidinglyreceived within an opening extending into the proximal tibial componentfrom a proximal end thereof. The tibial assembly may further include abearing plate having a distally facing bearing surface. The bearingplate may be engageable to the boss of the axle component at one of aplurality of locations along its length. The distally facing bearingsurface may correspond to the proximally facing bearing surface so as tointerface therewith when the bearing plate is engaged to the axlecomponent. The boss may include an array of transverse grooves disposedalong its length at predetermined intervals, and the bearing plate mayinclude first and second bearing portions that each may each include aflange configured to engage a respective transverse groove of the boss.The axle component may define an opening extending through the bossalong its length, and the proximal tibial component and axle componentmay include internal threads situated along their respective openings sothat when the boss is received within the opening of the proximal tibialcomponent, the internal threads of the boss are disposed adjacent theinternal threads of the proximal tibial component. The axle may have alongitudinal length that is smaller than a distance between the firstand second condylar portions.

Continuing with this aspect, the tibial assembly may include a baseplatecomponent having a tray portion and a boss extending from the trayportion. The distal end of the tibial assembly may include a bone facingsurface of the tray portion that is configured to connect to a resectedproximal tibia. Also, the tibial assembly may further include a modulartibial insert that defines the proximally facing bearing surface and isreceived by the tray portion. The axle component may include a bossslidingly received within an opening extending into the baseplatecomponent and along the boss thereof. The tibial assembly may furtherinclude a bearing plate having a distally facing bearing surface. Thebearing plate may be engageable to the boss of the axle component at oneof a plurality of locations along its length. The distally facingbearing surface may correspond to the proximally facing bearing surfaceso as to interface therewith when the bearing plate is engaged to theaxle component. The boss of the axle component may include an array oftransverse grooves disposed along its length at predetermined intervals,and the bearing plate may include first and second bearing portions thateach include a flange configured to engage a respective transversegroove of the boss. The axle component may define an opening extendingthrough the boss thereof along its length, and the baseplate componentand axle component may include internal threads situated along theirrespective openings so that when the boss is received within the openingof the baseplate component, the internal threads of the boss aredisposed adjacent the internal threads of the proximal tibial component.

Furthermore, the femoral assembly may include a shuttle slidinglydisposed between the first and second condylar portions and adjacent therecess. The shuttle may have a first position in which the recess isexposed so as to receive the axle and a second position in which theshuttle covers the recess so as to retain the axle within the recess.The shuttle may include flanges extending from opposite sides thereof,and the first and second condylar portions may each define slots thatslidingly receive respective flanges of the shuttle. The femoralassembly may include a diaphyseal portion that extends from the distalfemoral component and may be configured to connect to a femur that hasbeen resected along a diaphysis thereof. The distal femoral componentmay include a plurality of resection slots extending through the firstand second condylar portions for resecting a distal femur. The distalfemoral component may include a bone interface surface configured tointerface with previously resected surfaces of a distal femur. Thefemoral assembly may further include a stem adapter and theintercondylar portion may include an adaptor connection member. The stemadaptor may have a stem connection portion that may have a threadedopening for threaded connection to an intramedullary stem and a postthat may extend from the stem connection portion. The adaptor connectionmember may include a post opening configured to receive the post. Thestem adaptor may also include a locking pawl rotatably connected to thestem adaptor, and the adaptor connection member may include a latchopening disposed adjacent to the post opening so that when the post isdisposed in the post opening the locking pawl engages the latch opening.The post may define a first longitudinal axis and the stem connectionmember may define a second longitudinal axis. The first and second axesmay intersect at an oblique angle. The femoral assembly may furtherinclude first and second screws. The first condylar portion may define athreaded opening extending therethrough for threadedly engaging thefirst screw, and the second condylar portion may define a threadedopening extending therethrough for threadedly engaging the second screw.

In another aspect of the present disclosure, a method of preparing aknee joint to receive a hinge knee prosthesis includes mounting a tibialtrial assembly to a tibia and a femoral trial assembly to a femur;connecting an axle of tibial trial assembly to the femoral trialassembly by inserting the axle into a recess disposed between a firstand second condylar portions of the femoral trial assembly; assessingpatellofemoral and tibiofemoral kinematics by rotating the knee jointabout the axle through flexion and extension; and resecting the distalfemur through resection slots extending through the first and secondcondylar portions of the femoral trial assembly.

Additionally, the method may include removing a previously implantedknee prosthesis from the femur and tibia. The mounting step may includeengaging surfaces of the distal femur resected in a previous surgicalprocedure with an interior surface of a femoral component of the femoraltrial assembly. The method may also include further resecting a proximalend of the tibia, reaming an intramedullary canal of the tibia, andreaming an intramedullary canal of the femur. Resecting the tibia andreaming the tibia and femur may be performed before the mounting step,and resecting the distal femur may be performed after the mounting step.The connecting step may include sliding a shuttle of the femoral trialassembly over the axle and recess so as to retain the axle within therecess. Also, the method may include adjusting a proximal-distalposition of the femoral trial assembly relative the femur and a patellaby rotating a screw extending through one of the first and secondcondylar portions and in contact with the femur.

Continuing with this aspect, the method may include moving an axlecomponent that comprises the axle relative to a baseplate component ofthe tibial trial assembly while the axle is connected to the femoraltrial assembly so as to adjust the distance between the baseplatecomponent and femoral trial assembly. The moving step may includesliding a boss of the axle component through an opening in the baseplatecomponent. Also, the moving step may include moving the axle componentfrom a first set position to a second set position. The moving step mayinclude disengaging a first groove disposed along the length of the bosswith a bearing plate, and engaging a second groove offset from the firstgroove with the bearing plate. The first groove may be associated withthe first set position, and the second groove may be associated with thesecond set position. The bearing plate may have a distally facingbearing surface that interfaces with a proximally facing bearing surfaceof the tibial trial assembly when the axle component is in both thefirst and second set positions.

In a further aspect of the present disclosure, a method of preparing aknee joint to receive a hinge knee prosthesis includes resecting a femurand tibia; mounting a tibial trial assembly to the tibia and a femoraltrial assembly to the femur; connecting an axle of an axle component ofthe tibial trial assembly to the femoral trial assembly; assessingpatellofemoral and tibiofemoral kinematics by rotating the knee jointabout the axle through flexion and extension; and moving the tibialtrial assembly relative to the femoral trial assembly from a firstpredetermined distance to a second predetermined distance while the axleremains connected to the femoral trial assembly.

Additionally, resecting the femur may be performed after the mountingstep. However, resecting the femur may be performed before the mountingstep. In addition, resecting the femur may include resecting a cancerousportion of the femur. Also, resecting the tibia may include resecting acancerous portion of the tibia. The connecting step may includeinserting the axle into a recess disposed between first and secondcondylar portions of the femoral trial assembly. The moving step mayinclude inserting a threaded tool into an opening within a boss of theaxle component, engaging internal threads defined the boss and definedby a tibial component within which the boss is received, and rotatingthe threaded tool to distract the axle component relative to tibialcomponent. The moving step may be performed with the tibia and femurbeing in about 90 degrees of flexion. Also, the moving step may includedisengaging a first groove disposed along the length of the boss with abearing plate, and engaging a second groove offset from the first groovewith the bearing plate. The first groove may be associated with thefirst predetermined distance, and the second groove may be associatedwith the second predetermined distances. Also, the axle may be rigidlyfixed and immoveable relative to the shaft portion of the axlecomponent, and the bearing surface may be disposed entirely between thecondylar portions.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, aspects, and advantages of the present invention willbecome better understood with regard to the following description,appended claims, and accompanying drawings in which:

FIG. 1 is a perspective view of a hinge knee trial assembly thatincludes a tibial trial assembly and femoral trial assembly according toan embodiment of the present disclosure.

FIG. 2A is a perspective view of a baseplate trial of the tibial trialassembly of FIG. 1.

FIG. 2B is a cross-sectional view of the baseplate trail of FIG. 2Ataken along a midline thereof.

FIG. 3A is a perspective view of an intercondylar axle component of thetibial trial assembly of FIG. 1.

FIG. 3B is a partial cutaway view of the intercondylar axle component ofFIG. 3A.

FIG. 4A is a top perspective view of a tibial insert of the tibial trialassembly of FIG. 1.

FIG. 4B is a bottom perspective view of the tibial insert of FIG. 4A.

FIG. 5A is a top perspective view of a bearing plate of the tibial trialassembly of FIG. 1.

FIG. 5B is a bottom perspective view of the bearing plate of FIG. 4B.

FIG. 6 is a top perspective view of a keel trial of the tibial trialassembly of FIG. 1.

FIG. 7A is front perspective view of the baseplate trial, tibial insert,keel trial, and intercondylar axle component of the tibial trialassembly of FIG. 1, as assembled.

FIG. 7B is a side perspective view of the baseplate trial, keel trial,and intercondylar axle component of the tibial trial assembly of FIG. 1,as assembled.

FIG. 7C is a bottom perspective view of the tibial insert, keel trial,and intercondylar axle component of the tibial trial assembly of FIG. 1,as assembled.

FIG. 7D is a cutaway view of the baseplate trial and intercondylar axlecomponent of the tibial trial assembly of FIG. 1, as assembled.

FIG. 7E is a rear perspective view of the bearing plate andintercondylar axle component the tibial trial assembly of FIG. 1, asassembled.

FIG. 7F is a front perspective view of FIG. 7E.

FIG. 8A is a side perspective view of the femoral trial assembly of FIG.1 including augment trials and a valgus adaptor.

FIG. 8B is a top perspective view of a femoral component trial/guide ofthe femoral trial assembly of FIG. 8A.

FIG. 8C is a bottom perspective view of the femoral componenttrial/guide of FIG. 8B.

FIG. 8D is a top perspective view of a locking shuttle of the femoraltrial assembly of FIG. 8A.

FIG. 8E is a bottom perspective view of the femoral componenttrial/guide and locking shuttle of the femoral trial assembly of FIG.8A, as assembled.

FIG. 8F is a side view of the femoral component trial/guide and lockingshuttle of the femoral trial assembly of FIG. 8A, as assembled.

FIG. 8G is a rear view of the femoral component trial/guide and lockingshuttle of the femoral trial assembly of FIG. 8A, as assembled.

FIG. 9A is a perspective view of the augment trial of FIG. 8A.

FIG. 9B is a perspective view of the augment trial and femoral componenttrial guide of the femoral trial assembly of FIG. 8A, as assembled.

FIG. 10A is a perspective view of the valgus adaptor of FIG. 8A.

FIG. 10B is a side view of the valgus adaptor of FIG. 8A.

FIG. 11 is a perspective view of a distalizing screw of the femoraltrial assembly of FIG. 1.

FIG. 12A is a front view of the femoral trial assembly and intercondylaraxle component of the assembly of FIG. 1, as assembled in a firstconfiguration.

FIG. 12B is a front view of the femoral trial assembly and intercondylaraxle component of the assembly of FIG. 1, as assembled in a secondconfiguration.

FIG. 13 is a perspective view of a femoral oncology trial according toan embodiment of the present disclosure.

FIG. 14A is a perspective view of an alignment handle according to anembodiment of the present disclosure.

FIG. 14B is a perspective view of the alignment handle in engagementwith the tibial baseplate trial of FIG. 2A.

FIGS. 15A-15N depict a method of preparing a femur and tibia for a hingeknee prosthesis in a revision procedure according to an embodiment ofthe present disclosure.

FIGS. 16A-16H depict a method of preparing a femur and tibia for a hingeknee prosthesis in an oncology procedure involving a cancerous femur.

FIGS. 17A-17J depict a method of preparing a femur and tibia for a hingeknee prosthesis in an oncology procedure involving a cancerous tibia.

FIG. 18A depicts a method of preparing a tibia for a hinge kneeprosthesis in a revision procedure according to another embodiment ofthe present disclosure.

FIG. 18B depicts a method of preparing a femur for a hinge kneeprosthesis in a revision procedure according to a further embodiment ofthe present disclosure.

DETAILED DESCRIPTION

When referring to specific directions in the following discussion ofcertain devices, it should be understood that such directions aredescribed with regard to the device's orientation and position duringexemplary application to the human body. Thus, as used herein, the term“proximal” means closer to the heart, and the term “distal” meansfurther from the heart. The term “anterior” means toward the front partof the body or the face, the term “posterior” means toward the back ofthe body. The term “medial” means closer to or toward the midline of thebody, and the term “lateral” means further from or away from the midlineof the body. The term “inferior” means closer to or toward the feet, andthe term “superior” means closer to or toward the crown of the head. Asused herein, the terms “about,” “generally,” and “substantially” areintended to mean that slight deviations from absolute are includedwithin the scope of the term so modified.

FIG. 1 depicts a hinge knee trial assembly 10 according to an embodimentof the present disclosure. Hinge knee trial assembly 10 includes afemoral trial assembly 14 and a tibial trial assembly 12. Tibial trialassembly 12 generally includes a baseplate component 20, axle component40, tibial insert 60, bearing plate 70, and keel trial 80 (see FIG. 7B).

FIGS. 2A and 2B depict baseplate component 20. Baseplate component 20includes a tray portion 30 and a boss 22. Boss 22 extends from a distalside of tray portion 30 and defines a boss opening 28 that extendsentirely through boss 22 and through tray portion 30. Boss opening 28 issized to slidingly receive a boss 50 of axle component 40, as describedfurther below. Boss 22 includes internal threads 24 at a distal endthereof while the remainder of boss 22 defines a smooth bore. Theinterface of the smooth bore and threads 24 forms a shelf 26, as shownin FIG. 2B. Internal threads 24 are configured to threadedly engageexternal threads of a stem trial 21 (see FIG. 15H).

Tray portion 30 includes a proximal plate surface 32 that has a rim 35extending partially about its perimeter which forms a dish that isconfigured to receive tibial insert 60. Keel slots 38 extend throughtray portion 30 adjacent boss 22. An anterior protrusion 34 extends fromplate surface 32 and defines an anterior opening 36 that is configuredto receive a cylindrical projection 98 of an alignment handle 90, as isdescribed below. A distal surface 33 of tray portion 30 is configured tobe mounted onto a resected proximal tibia. Tibial augments (not shown)can be coupled to distal surface 33 as necessary to accommodate bonedeficiencies that may be realized during a revision procedure, forexample.

FIGS. 3A and 3B depict axle component 40. Axle component 40 includes anaxle 46, axle support 44, base 42 and boss 50. Boss 50 projects frombase 42 in a distal direction. Boss 50 includes a shaft portion 52. Adistal end of the cylindrical shaft portion 52 is beveled to form ashoulder 55. In some embodiments, a second cylindrical shaft portion(not shown) may extend coaxially from shaft portion 52 and may have asmaller diameter than shaft portion 52 to form the shoulder 55.

An array of engagement grooves 56 is disposed along the length of shaftportion 52 so that individual grooves 56 of the array are spaced atpredetermined intervals. These grooves 56 extend into an outer surfaceof shaft portion 52 and in an anterior-posterior direction. Each groove56 on one side of shaft portion 52 is paired with a corresponding groove56 at the opposite side of shaft portion 52. Each of these pairs ofgrooves 56 are associated with indicia 58 that indicate a tibial insertthickness to be used for the final hinge prosthesis. Thus, the distancebetween each groove 56 in a proximal-distal direction corresponds to adifference in thickness between different sized tibial inserts. A toolopening 53 extends through shaft portion 52 and along the lengththereof. Internal threads 51 are disposed at a distal end of shaftportion 52. The remainder of shaft portion 52 proximal to internalthreads 51 defines a smooth bore 57.

Axle support 44 extends proximally from base 42 and is offsetposteriorly from boss 50. Such offset helps provide clearance so thattool opening 53 can be easily accessed by a tool. Axle support 44, asshown, has a substantially rectangular cross-sectional geometry. Axle 46is attached at a proximal end of axle support 44. Axle 46 issubstantially cylindrical and defines a longitudinal axis that extendsin a lateral-medial direction transverse to a longitudinal axis definedby boss 50. Axle 46 has a length that is less than a distance betweencondylar portions 122 of a femoral component 100 of femoral trialassembly 14 which allows axle 46 to be passed therebetween into anintercondylar space, as is described in more detail below. Moreover,axle 46, as depicted, is rigidly fixed and immoveable relative to shaftportion 52. In this regard, axle does not have moving parts which aresusceptible to failure under normal operating conditions. However, itshould be understood that axle could be modularly connectable to shaftportion 52.

FIGS. 4A and 4B depict tibial insert 60. Tibial insert 60 includesbearing portions 62 that define proximally facing bearing surfaces 64that are preferably concavely curved in a sagittal plane. Anintrabearing recess 66 partially separates bearing portions 62. Atdistal side of insert 60 opposite that of bearing surfaces 64, insert 60includes indented surfaces 68 that flank recess 66 from two sides, asbest shown in FIG. 4B. Such indented surfaces 68 provide clearance for abridge 84 of keel trial 80. An anterior notch 69 is also located on thesame side of insert 60 as indented surfaces 68. Such notch 69 providesclearance for anterior protrusion 34 of baseplate 20.

FIGS. 5A and 5B depict bearing plate 70. Bearing plate 70 includesbearing portions 72 that define distally facing bearing surfaces 75 thatare preferably convexly curved in a sagittal plane so as to correspondwith proximally facing bearing surfaces 64 of tibial insert 60. Anintrabearing elongate opening 74 partially separates bearing portions72. In addition, anterior flanges 78 extend proximally from bearingplate 70 adjacent opening 74. A viewing notch 71 extends betweenanterior flanges 78 in an anterior-posterior direction which allowsindicia 58 of axle component 40 to be viewed therethrough when axle boss50 is disposed within opening 74. Each bearing portion 72 includes anelongate flange 76 that extends into opening 74. Such flanges 76 areconfigured to slidingly engage corresponding pairs of grooves 56 of axlecomponent 40. However, flanges 76 do not extend along the entire lengthof opening 74 so that flanges 76 can disengage one pair of grooves 56and then engage another pair of grooves 56 without having to remove boss50 from opening 74.

FIG. 6 depicts keel trial 80. Keel trial 80 includes keel portions 82that are connected by a bridge 84. Such bridge 84 defines a semicircularrecess 86 that is configured to extend about a portion of axle boss 50when keel trial 80 is connected to baseplate component 20.

FIGS. 7A-7F illustrate the interconnection of components of tibial trialassembly 12. In this regard, as assembled, keel portions 82 of keeltrial 80 extend distally through corresponding keel slots 38 inbaseplate component 20. Bridge 84 of keel trial 80 is positionedposterior to boss opening 28 and spans between keel slots 38, as bestshown in FIG. 7B. Tibial insert 60 rests on proximal plate surface 32and is received by the dish defined by tray portion 30. In addition,indented surfaces 68 rest on bridge 84 of keel trial 80, as best shownin FIG. 7C.

Axle boss 50 is slidingly disposed within boss opening 28 of baseplatecomponent 20 so that indicia 58 face anteriorly. In this regard, axleboss 50 can slide in a proximal-distal direction as well as rotate abouta longitudinal axis thereof. When boss 50 is fully inserted into bossopening 28, shoulder 55 of boss 50 rests against shelf 26 of boss 22,and internal threads 51 of boss 50 are positioned adjacent internalthreads 24 of boss 22. This allows a threaded tool to engage internalthreads 51 and abut a stem trial engaged to internal threads 24 to helpdistract axle component 50 and baseplate component 20, as is describedbelow.

Bearing plate 70 is attached to boss 50 of axle component 40, as shownin FIGS. 7E and 7F. In this regard, flanges 76 slidingly engage acorresponding pair of grooves 56 which constrains bearing plate 70 in aproximal-distal direction relative to axle component 40. However,bearing plate 70 can slide anteriorly to disengage the grooves 56. Thisallows bearing plate 70 to engage any pair of corresponding grooves 56.When flanges 76 of bearing plate engage such grooves 56, viewing notch71 aligns with corresponding indicia 58 indicating a tibial insert size(best shown in FIG. 7F). With bearing plate 70 engaged to boss 50,bearing plate 70 rests on tibial insert 60 so that distally facingbearing surfaces 75 interface with proximally facing bearing surfaces 64(best shown in FIG. 1).

Tibial trial assembly 12, as previously described, allows axle 46 to bemoved from one set position to another set position in a proximal-distaldirection relative to baseplate component 20. In this regard, whenbearing plate 70 is engaged to a first pair of grooves 56 and bearingplate 70 rests on tibial insert 60, axle 46 is located a firstpredetermined distance from baseplate 20. However, when bearing plate 70engages a second pair of grooves 56 and bearing plate 70 rests on tibialinsert 60, axle 46 is located a second predetermined distance frombaseplate component 20 that is different from the first predetermineddistance.

Referring back to FIG. 1 and also to FIG. 8A, femoral trial assembly 14generally includes a femoral component 100, distalizing screws 160,valgus adaptor 150, and augment trial 140.

As depicted in FIGS. 8A-8E, femoral component 100 includes an anteriorflange portion 127, condylar portions 122 and an intercondylar portion110 disposed between condylar portions 122. Threaded openings 123 extendthrough condylar portions 122 in a proximal-distal direction. Inaddition, first, second, and third resection slots 124 a-c extendthrough condylar portions 122. In this regard, femoral component 100acts as both a trial and a cutting guide. Such slots 124 a-c areconfigured to guide a bone saw to perform two to three cuts of thefemur, such as an anterior chamfer cut, a posterior chamfer cut and adistal augment cut (optional). Resection slots 124 a-c define resectionplanes 125 a-c along which these cuts are performed, as best shown inFIG. 8F. For example a first cutting plane 125 a is defined by first andthird resection slots 124 a, 124 c, a second cutting plane 125 b isdefined by second resection slots 124 b, and a third cutting plane 125 cis defined by first and second resection slots 124 a-b. Femoralcomponent 100 includes guide flanges 126 extending from an exteriorsurface thereof that are aligned with first and second resection planes125 a-b adjacent first and second cutting slots 124 a-b, respectively,as these slots are each utilized for two of the three possible cuts thatare performed utilizing femoral component. These flanges 126 do notinterfere with articulation of femoral trial assembly 14 with tibialtrial assembly 12 as condylar portions 122 do not articulate with tibialtrial assembly 12.

Anterior flange 127 is configured to articulate with a patella. Pinholes 129 extend through anterior flange and are configured to receivebone pins. In addition, a pair of pin slots 128 extends through anteriorflange 127. These slots 128 are oriented so that a pin can be insertedthrough such slots 128 to prohibit proximal-distal movement of femoralcomponent 100 relative to a femur, while allowing femoral component 100to be rotated internally or externally relative to the femur.

Intercondylar portion 110 is configured to connect femoral component 100to axle component 40 and valgus adaptor 150. In this regard,intercondylar portion 110 is substantially located in a space betweencondylar portions 122 and includes an axle bearing member 111 and anadaptor connection member 112. Adaptor connection member 112 is disposedat an anterior side of femoral component 100 and defines a post opening114 and a latch opening 116. Post opening 114 extends in aproximal-distal direction into connection member 112 while latch opening116 extends into connection member 112 in a direction transverse to postopening 114. A pair of sidewalls 118 (see FIG. 8F) extends proximallyfrom connection member 112 and is disposed adjacent post opening 114.Such sidewalls 118 interface with flat surfaces 159 of valgus adaptor150 to prevent it from rotating relative to femoral component 100 whenconnected thereto.

Axle bearing member 111 includes contoured bearing surfaces 119, whichas shown in FIG. 8F, define a partially cylindrical recess 115. Suchrecess 115 extends in a lateral-medial direction between condylarportions 122 and is sized to receive axle 46. A posterior notch 113intersects the recess. Such notch 113 has a generally rectangulargeometry and is sized to receive axle support 44. A pair of guidegrooves 117 extends into the condylar portions 122 adjacent theintercondylar space and extends in an anterior-posterior direction, asbest shown in FIG. 8C. A locking shuttle 130 is slidingly connected tosuch guide grooves 117.

Locking shuttle 130 is depicted in FIG. 8D and includes a body portion131 and a pair of legs 132 extending from body portion 131. Legs 132 areseparated by a recess 134 and each incudes a flange 136 extendingoutwardly therefrom. These flanges 136 are configured to engage guidegrooves 117 of the femoral component 100. In addition, recess 134 issized and shaped to receive axle support 44. When connected to femoralcomponent 100, as is depicted in FIGS. 8E-8G, locking shuttle 130 slidesin an anterior-posterior direction so that in a first position, oranterior position, axle recess 115 is exposed, and in a second position,or posterior position, axle recess 115 is covered by shuttle 130. Thishelps lock axle 46 to femoral component 100.

Femoral component 100 can be utilized to trial and resect a distal femurin a revision procedure, and also utilized in an oncology procedurewhere the tibia has a cancerous growth and the femur adjacent themalignant tibia is pristine. In a revision procedure, the target distalfemur has already been resected in a previous procedure typically in afive-cut fashion involving a distal, posterior, anterior, anteriorchamfer, and posterior chamfer cuts, as is understood in the art. Thus,when femoral component 100 is utilized in a revision procedure, aninterior portion or proximal side of femoral component is placed in aninterfacing relationship with such resected surfaces. However, thegeneral objective is to convert the five-cut femur to a three-cut femur,as is understood in the art, in order to create space at a posteriorside of the distal femur for a hinge assembly of a hinge kneeprosthesis. In order for the interior portion of femoral component 100to conform to the five-cut femur so that it can be resected andtransformed to a three-cut femur, the interior portion of femoralcomponent 100 defines a first, second, and third bone contact surfaces101, 102, 103 where first bone contact surface 101 contacts a posteriorresected surface of the femur, second bone contact surface 102 contactsa distal resected surface, and third bone contact surface 103 contactsan anterior resected surface of the revision femur.

However, as mentioned femoral component 100 can also be utilized in anoncology procedure where a femur is pristine. In other words, the femuris in its natural state and has not been resected in a previousprocedure. In this situation, the pristine femur is cut using a distalresection guide 330 and a 3-in-1 cutting block 250 (see FIGS. 17E and17F) to form the femur into a three-cut femur for receipt of a hingeknee prosthesis. In order to utilize femoral component 100 for suchthree-cut femur, augment trials 140 are connected to first bone contactsurface 101 to create a conforming interior geometry of femoralcomponent 100 that is adapted to the three-cut femur, which allowsfemoral component 100 to be utilized in both revision and oncologyprocedures to trial a hinge knee prosthesis. Thus, femoral component 100has one configuration adapted to be mounted to a five-cut femur, and asecond configuration adapted to be mounted to a three-cut femur.

Augment trial 140, as depicted in FIG. 9A, includes a body 142, firstflange 141 a, second flange 141 b, and spring member 148. Body 142 isconstructed to conform to first bone contact surface 101 and a portionof second bone contact surface 102. In addition, body defines a chamfersurface 144 which takes the place of first bone contact surface 101 whenaugment trial is connected to femoral component 100. First flange 141 aextends from body 142 and aligns with chamfer surface 144. First flange141 a is sized to be received in second cutting slot 124 b, as shown inFIG. 9B. Second flange 141 b extends from a posterior side of body 142and is configured to be received in third cutting slot 124 c. Theseflanges 141 a-b connect augment trial 140 to femoral component 100. Body142 also defines a slot 146 which is aligned with flange 141 b so thatslot 146 operates as a replacement for third resection slot 124 c whenaugment trial is connected to femoral component 100 and second flange isconnected to third resection slot 124 c. Spring member 148 is disposedbetween flanges 141 a-b. Spring member 148 is cantilevered to body 142and is curved to conform to an interior of component 100 so that whenflanges 141 a-b are positioned in their associated resection slots 124a-b, the spring member 148 provides resistance which serves to holdtrial 140 in position via frictional engagement between flanges 141 a-band slots 124 a-b. Spring member 148 also prevents movement of trial 140relative to component 100 so that the operator can obtain an accurateassessment of fit.

FIGS. 10A-10B depict the valgus adaptor 150 which can be used to connectan intramedullary stem (not shown) to femoral component 100 and to alsoapply a desired valgus angle to femoral component 100 relative to thefemur. Valgus adaptor or stem adaptor 150 generally includes a stemconnection member 154, a post 158 and a locking pawl 152. Stemconnection member 154 is substantially cylindrical and defines anopening 151 that extends along its length. Opening 151 has internalthreads 153 for connection to an intramedullary stem. A slot extendsthrough the side of connection member 154. Locking pawl 152 is disposedwithin this slot and is rotatably connected to connection member 154.The distal end of connection member 154 adjacent post 158 has flat sidesurfaces 159 that interface with walls 118 of adaptor connection member112 so as to help prevent rotation of adaptor 150 relative to femoralcomponent 100. Post 158 extends from connection member 154 and has asmaller cross-sectional dimension than connection member 154. Post 158defines a longitudinal axis that intersects a longitudinal axis ofconnection member 154 at an oblique angle. This angle may be about 0 to9 degrees. However, this angle is preferably 6 degrees. Such angledefines the desired valgus angle of femoral component 100 relative to afemur.

FIG. 11 depicts distalizing screw 160. Distalizing screw 160 includes athreaded portion 162 and unthreaded portion 164. Threaded portion 162 isconfigured to threadedly engage a threaded opening 123 of the femoralcomponent 100. Screw 160 has a length sufficient to extend throughfemoral component 100 and contact a bone surface. Unthreaded portion 164is at an opposite end of screw 160 from the head 161 of screw 160 andterminates at a flat tip 168. Such flat tip 168 helps push against abone surface to distract femoral component 100 away from a bone surface,as is described in more detail below.

As mentioned above, femoral trial assembly 14 has a first configurationadapted to mount to a five-cut femur, such as for a revision procedure.In such assembly, distalizing screws 160 are threaded into threadedopenings 123, and valgus adaptor 150 is connected to adaptor connectionmember 112. In this regard, post 158 extends into post opening 114,locking pawl 152 is connected to latch opening 116, and sidewalls 118interface with surfaces 159. It is noted that latch opening 116 extendsentirely through connection member 112 so that valgus adaptor 150 can beconnected in two different orientations depending on which leg femoralcomponent 100 is mounted to. In this regard, femoral component 100 isuniversal to both a right and left leg of a patient.

In the second configuration of femoral trial assembly 14, which isadapted for mounting to a three-cut femur, valgus adaptor 150 isconnected to connection member 112 in the same manner as in the firstconfiguration, and augment trials 140 are additionally connected tofemoral component 100, as is shown in FIG. 8A. In this regard, twoaugment trials 140 are connected to opposite sides of femoral component100 so that chamfer surface 144 faces anteriorly and first and secondflanges 141 a-b thereof engage respective second and third cutting slots124 b-c.

Femoral trial assembly 14 can be connected to tibial trial assembly 12via axle member 40. In this regard, locking shuttle 130 is located atits anterior position to expose axle recess 115. Axle 46 is passedthrough an intercondylar space between first and second condylarportions 122 and into recess 115, as shown in FIG. 12A. The length ofaxle 46 is such that axle 46 can pass through this space lengthwise.When axle 46 is inserted into recess 115, axle support 44 is located inposterior notch 113 allowing unimpeded freedom of rotation of axlecomponent 40 relative to femoral component 100. To help retain axle 46within recess 115, locking shuttle 130 is slid into its posteriorposition so that legs 132 at least partially extend over axle 46, asshown in FIG. 12B. Recess 134 provides clearance for axle support 44when axle component 40 is rotated relative to femoral component 100through flexion and extension.

Tibial trial assembly 12 can be utilized to trial a tibia in a revisionprocedure, and also utilized in an oncology procedure where a femur hasa cancerous growth and the tibia adjacent the malignant femur ispristine. In such an oncology procedure, a significant portion of apatient's femur may be removed leaving only a portion of the femur'sdiaphysis at the femur's distal end. In this regard, femoral trialassembly 14 cannot be used in conjunction with tibial trial assembly asthere would be no bone for assembly 14 to connect. However, analternative femoral trial may be utilized.

FIG. 13 depicts a femoral oncology trial 200 which may be used as analternative to femoral trial assembly 14 for femoral oncologyprocedures. Trial 200 includes a distal femoral component 204 and adiaphyseal extension member 202. Distal femoral component 204 includes ametaphyseal portion 203 and a diaphyseal portion 205. Diaphyseal portion205 extends from metaphyseal portion 203 and is configured to connect toa resected diaphysis of a femur or, alternatively, to diaphysealextension member 202. Metaphyseal portion 203 defines condylar portions201 and an intercondylar portion 207. Intercondylar portion 207 issimilar to intercondylar portion 110 in that it includes an axle recess,anterior notch and locking shuttle 206. This allows femoral oncologytrial 200 to be connected to tibial trial assembly 12 in the samefashion as femoral trial assembly 14.

In other oncology procedures where a tibia has a cancerous growth,tibial trial assembly 12 cannot be utilized as the patient's proximaltibia may be completely removed to eliminate the cancerous growth.However, alternatives may be utilized that can operate in conjunctionwith femoral trial assembly 14 or femoral oncology trial 200. One suchalternative is tibial oncology trial 220 depicted in FIG. 17I. Tibialoncology trial 220 includes a proximal tibial component 224 and adiaphyseal extension member 227. Proximal tibial component 224 includesa metaphyseal portion 225 and a diaphyseal portion 226. Diaphysealportion 226 extends from metaphyseal portion 225 and is configured toconnect to a resected diaphysis of a tibia or, alternatively, todiaphyseal extension member 227. Metaphyseal portion 225 defines a trayportion 228 at its proximal end that is configured to receive tibialinsert 60. In addition, metaphyseal portion 225 defines a boss opening(not shown) that is configured to receive boss of axle component 40 sothat tibial oncology trial 220 can operate in a similar fashion to thatof tibial trial assembly 12.

Other instruments may be utilized in conjunction with hinge knee trialassembly 10. For example, FIGS. 14A and 14B depict an alignment handle90. Alignment handle 90 can be used to assess alignment of baseplatecomponent 20 relative to a patient's tibia. Handle 90 includes anelongate body 92 and an engagement end 91. Openings 94 extend throughelongate body 92 and are configured to receive an extramedullary rod.Engagement end 91 includes stabilizing flanges 96 and a cylindricalprojection 98. Cylindrical projection 98 is configured to extend intoanterior opening 36 of baseplate component 20 while flanges 96 contactproximal plate surface 32 to orient and stabilize handle 90 to preventhandle 90 from rotating, as shown in FIG. 14B.

As mentioned above, hinge knee trial assembly 10 and the variouscomponents thereof, may be utilized in various different surgicalprocedures, such as revision procedures and oncology procedures.However, it should be understood that such devices could be utilized inother procedures, such as in a primary TKA, in which a hinge kneeprosthesis is to be implanted.

FIGS. 15A-15N illustrate a method of preparing a knee joint utilizinghinge knee trial assembly 10 in a revision procedure. In the method,after an operator gains access to the patient's knee joint, a previouslyimplanted prosthesis is removed from a femur 420 and tibia 410 to exposethe proximal tibia and distal femur. As is typically the case in arevision procedure, the proximal tibia and distal femur have resectedsurfaces which were formed in the previous procedure in which theprevious prosthesis was implanted. In this regard, the tibia 410 has aresected proximal surface. In addition, femur 420 may be a five-cutfemur in which femur 420 has anterior, anterior chamfer, distal,posterior chamfer, and posterior resected surfaces 421-425, as bestshown in FIG. 15K.

Once the previously implanted prosthesis is removed, tibia 410 isprepared to receive tibial trial assembly 12. In this regard, flutedreamers are sequentially advanced into the intramedullary canal leavingthe last reamer 310 in situ so that a shank 312 of reamer 310 extendsfrom the proximal tibia (see FIG. 15A). Thereafter, a resection jig 330is assembled to reamer shank 312 so that a resection slot 332 ofresection jig 330 is placed adjacent to tibia 410 (see FIG. 15B). Therotational alignment of cutting jig 330 is verified by connectingalignment handle 90 to jig 330 which is achieved by insertingcylindrical projection 98 into a corresponding opening 334 of resectionjig and placing stabilizing flanges 96 on respective surfaces 336 of jig330. An extramedullary rod 340 is inserted through opening 94 in handle90 and is used to reference the alignment of resection slot 332 relativeto an axis of tibia 410. When the desired alignment is achieved, jig 330is pinned to tibia 410 (see FIG. 15C) via bone pins 350, and a saw 360is inserted through resection slot 332 to perform a clean-up skim cut ofthe proximal tibia (see FIG. 15D). If necessary, appropriate augmentcuts may be performed through other resection slots in jig 330.Thereafter, jig 330 is removed from shank 312 of intramedullary reamer310 and a cannulated boss reamer 370 reams into tibia over shank 312 soas to form a bone void for receipt of boss 22 of tibial baseplate 20(see FIG. 15E). Reamer 310 is then removed.

Femur 420 is also prepared so that it can receive femoral trial assembly14. In this regard, fluted reamers are sequentially advanced into theintramedullary canal of the femur leaving the last reamer 310 in situ sothat shank 312 of reamer 310 extends from the distal femur (see FIG.15F). A cannulated boss reamer 372 reams femur 420 over shank 312 so asto form a void for valgus adaptor 150. Reamer 310 is then removed fromfemur 420.

Once tibia 410 is prepared, a stem trial 21 is connected to baseplatecomponent 20 by threading stem trial 21 to internal threads 24 ofbaseplate boss 22. An introducer 380 is connected to baseplate component20. Baseplate component 20 and stem trial 21 are inserted into theintramedullary canal and introducer 380 is impacted to seat distalsurface 33 of tray portion 30 against the proximal resected surface oftibia 410 (see FIG. 15G). Rotational alignment of baseplate component 20is verified by connecting alignment handle 90 to tray portion 30 so thatcylindrical projection 98 is received in anterior opening 36 andstabilizing flanges 96 rest on proximal plate surface 32 (see FIG. 15H).An extramedullary rod 340 connected to handle 90 is observed relative toan axis of tibia 410 and adjustments are made when necessary.

Once alignment and rotation of baseplate component 20 is verified, akeel punch 390 is inserted through keel slots 38 of baseplate component20 and impacted so as to form spaces in tibia 410 for keel trial 80 (seeFIG. 15I). Thereafter, keel trial 80 is assembled to baseplate component20 by inserting keel portions 82 through keel slots 38 and positioningbridge on proximal plate surface 32 between keel slots 38 (see FIG.15J).

Thereafter, tibial insert 60 is mounted onto plate portion 30 and keeltrial 80. Bearing plate 70 is engaged to axle component 40 by engaging afirst pair of grooves 56 with flanges 76 of bearing plate 70. Boss 50 ofaxle component 40 is inserted into boss opening 28 of baseplatecomponent 20 until shoulder 55 comes to rest on shelf 26, and/or untilbearing component 70 rests on tibial insert 60.

Once femur 420 is prepared for femoral trial assembly 14, femoral trialassembly 14 is mounted to the distal femur (see FIG. 15K). In thisregard, an appropriate valgus adaptor 150 is selected depending on thedesired valgus angle. Valgus adaptor 150 is then connected to femoralcomponent 100 by inserting post 158 into post opening 114 until lockingpawl 152 latches to latch opening 116. A stem trial 170 is connected tovalgus adaptor 150 via internal threads 151. Also, distalizing screws160 are inserted into respective threaded openings 123 in condylarportions 122. It is noted that femoral component 100 does not includeaugment trials 140 for this method involving a revision femur. Oncefemoral trial assembly 14 is assembled, stem 170 is inserted into femur420 and femoral component 100 may be mounted to the distal femur so thatfirst bone contact surface 101 contacts posterior resected surface 425.However, in many cases, first bone contact surface 101 may not contactposterior resected surface 425 due to posterior bone loss. In addition,second bone contact surface 102 contacts distal resected surface 423,and third bone contact surface 103 contacts anterior resected surface421. Anterior chamfer and posterior chamfer resected surfaces 422, 424may not be contacted or contacted in any significant way.

After the tibial trial assembly 12 is mounted to tibia 410, and femoraltrial assembly 14 is mounted to femur 420, tibial trial assembly 12 andfemoral trial assembly 14 are connected (see FIG. 15L). In this regard,axle 46 is inserted into recess 115 of femoral component 100 betweencondylar portions 122. Locking shuttle 130 is moved into its posteriorposition to lock axle 46 into place.

Once assemblies are connected, joint kinematics and joint alignment isassessed. In particular, the patient's patella is observed relative tofemoral component 100 to assess for patella baja or patella altaconditions. In the event of a patella baja condition, femoral component100 can be adjusted distally to align femoral component 100 with thepatella. This is achieved by turning distalizing screws 160 with awrench 400 which causes screws 160 to push against distal resectedsurface 423 so as to distract femoral component 100 relative to femur420 (see FIG. 15M). Once the desired alignment of femoral component 100relative to the patella is achieved, a pin 352 is inserted into bonethrough pin slot 128, which constrains femoral component 100 in aproximal-distal direction while allowing for internal/external rotationthereof. Internal/external rotation of femoral component 100 may beassessed relative to a bony landmark. Once rotational alignment isachieved, a pin 352 is inserted through one or more pinholes 129 tocompletely constrain femoral component 100 relative to femur 420.

Kinematic assessment of the joint is continued by rotating tibia 410relative to femur 420 through flexion and extension to assess tightnessor instability of the joint. Where more tension in the joint isdesirable, the knee is flexed to about 90 degrees of flexion. Tibialinsert 60 and bearing plate 70 are preferably removed. Although in someembodiments, they may remain in place. Wrench 400, which has a threadeddistal end 404, is inserted into tool opening 53 of axle component 40 sothat threads 404 engage internal threads 51 of axle boss 50 (see FIG.15N). Wrench 400 is turned clockwise which causes wrench 400 to advancedistally until it contacts a proximal end of stem trial 21 which resiststhe wrench's advancement causing axle component 40 to be advancedproximally relative to baseplate component 20 which distracts assemblies12 and 14. This is performed until bearing component 70 can be engagedto a second pair of grooves 56 and while axle 46 remains disposed withinbearing recess 115. In this regard, bearing plate 70 is engaged to asecond pair of grooves 56 located more distal than the first pair ofgrooves 56 and insert 60 is mounted back onto tray portion 30. Wrench400 is removed from axle component 40 and bearing component 70 isallowed to once again contact insert 60. At this point, femoral trialassembly 14 is more distant from tibial trial assembly 12 than whenbearing plate 70 was engaged to the first pair of grooves 56. Jointkinematics are re-evaluated and the distance between assemblies 12 and14 is adjusted again as necessary. Once the appropriate separationbetween assemblies 12 and 14 is achieved, the operator reads indicia 58through viewing notch 71 which indicates to the operator the appropriatesized insert 60 for use in the final hinge knee prosthesis.

Once the joint kinematics and alignment are as desired, distalizingscrews 160 are removed from femoral component 100. A bone saw is thenused to resect femur 420 along second and third planes 125 b-c whichconverts distal femur 100 from a five-cut femur to a three-cut femurcapable of receiving a hinge knee prosthesis. A bone saw may optionallybe used to perform an augment cut along first resection plane 125 a toaccount for bone deformities in the distal femur. Thereafter, assemblies12 and 14 are removed from their respective bones and the hinge kneeprosthesis is implanted. This method is particularly beneficial at leastbecause it allows an operator to assess joint kinematics and adjustassemblies 12 and 14 to determine the proper alignment and proper tibialinsert size for the final prosthesis before resecting the femur. Inaddition, kinematic assessment and adjustments may be performed withoutdisassembling assemblies 12 and 14.

FIGS. 16A-16H illustrate another method embodiment in which tibial trialassembly 12 and femoral oncology trial 200 are utilized to prepare atibia 510 and femur 520 for a final prosthesis. In this regard, tibia510 may be pristine or otherwise in its natural condition, while femur520 includes a cancerous growth 522 at its distal end. In the method, adistal femoral template 600 is used to reference the joint line and marka location for resection that ensures complete removal of the cancerousgrowth 522 (see FIG. 16A). Rotational alignment is also marked on thefemoral shaft (see FIG. 16B). Reference measurements may also be madethat can be later verified to help ensure leg length is restored (seeFIG. 16C).

After the appropriate markings and measurements are completed, a femoralosteotomy is performed by resecting via bone saw 620 along the femoraldiaphysis perpendicular to the femoral shaft axis (see FIG. 16D). Areamer 610 is then used to ream the intramedullary canal and to planethe osteotomy site so as to ensure accurate seating of femoral oncologytrial 200 and the final prosthesis (see FIG. 16E).

As mentioned, tibia 510 may be pristine and is, therefore, resected toprepare tibia 510 for tibial trial assembly 12. In this regard, flutedreamers are sequentially advanced into the intramedullary canal of thetibia leaving the last reamer 310 in situ so that the shank 320 ofreamer 310 extends from the proximal tibia. Resection jig 330 isconnected to reamer shank 320 and a stylus 630 is connected to resectionjig 330 so that stylus 630 contacts the proximal tibia as reference (seeFIG. 16F). Rotational alignment of resection jig 330 may be assessed viaalignment handle 90 as previously described. Jig 330 is then pinned tothe proximal tibia. A bone saw is advanced through a resection slot toresect tibia 510 and form a resected proximal surface. Resection jig 330is then removed and a boss reamer is used to further ream the proximaltibia. Reamer 310 is then removed from tibia 510.

Once tibia 510 is prepared for tibial trial assembly 12, tibial trialassembly 12 is assembled and mounted to tibia 510 as described abovewith regard to the revision method. Femoral oncology trial 200 is alsoassembled by attaching appropriate diaphyseal extensions 202, asnecessary, to diaphyseal portion 205 of distal femoral component 204.Femoral oncology trial 200 is mounted onto femur 520. Thereafter, tibialtrial assembly 12 and femoral oncology trial 200 are connected. In thisregard, axle 46 is inserted into a bearing recess of distal femoralcomponent 204 between condylar portions 201. Locking shuttle 206 ismoved into a posterior position to lock axle 46 into place (see FIG.16G).

Patella tracking and overall joint kinematics is evaluated by rotatingtibial assembly 12 relative to femoral oncology trial 200 and about axle46. If more distance between assemblies 12 and 200 is required, the kneeis flexed to about 90 degrees and tibial insert 60 is removed from trayportion 20 and bearing component 70 is disengaged from a first pair ofgrooves 56. Threaded wrench 400 is inserted into the axle so as toengage internal threads 51 (see FIG. 16H). Wrench 400 is turnedclockwise which distracts tibial trial assembly 12 and femoral trialassembly 200. This is performed until bearing component 70 can beengaged to a second pair of grooves 56 and while axle 46 remainsdisposed within the bearing recess of distal femoral component 204. Inthis regard, bearing component 70 is engaged to a second pair of grooves56 located more distal than the first pair of grooves 56 and insert 60is mounted back onto tray portion 30. Wrench 400 is removed from axlecomponent 40 and bearing component 70 is allowed to once again contactinsert 60. At this point, femoral oncology trial 200 is more distantfrom tibial trial assembly 12 than when bearing component 70 was engagedto the first pair of grooves 56. Joint kinematics are re-evaluated andthe distance between assemblies 12 and 200 is adjusted again asnecessary. Once the appropriate separation between assemblies 12 and 200is achieved, the operator reads indicia 58 through viewing notch 71which indicates to the operator the appropriate sized tibial insert foruse in the final hinge knee prosthesis. The assemblies 12 and 200 arethen disassembled and the final hinge knee prosthesis is implanted.

FIGS. 17A-17J illustrate a further method embodiment in which tibialoncology trial 220 and femoral trial assembly 14 are utilized to preparea tibia 710 and femur 720 for a final prosthesis. In this regard, femur720 may be pristine or otherwise in its natural condition, while tibia710 includes a cancerous growth 722 at its proximal end. In the method,reference measurements may be made that can be later verified to helpensure leg length is restored (see FIG. 17A). A tibial template 700 isthen used to reference the joint line and mark a location for resectionthat ensures complete removal of the cancerous growth (see FIG. 17B).

After the appropriate markings and measurements are performed, a tibialosteotomy is performed by resecting via a bone saw 620 along thediaphysis of tibia 710 perpendicular to the tibial shaft axis (see FIG.17C). A reamer is then used to ream the intramedullary canal of tibia710 and to plane the osteotomy site so as to ensure accurate seating oftibial oncology trial 220 and the final prosthesis.

As mentioned, femur 720 may be pristine and is, therefore, resected toprepare femur 720 for femoral trial assembly 14. In this regard, flutedreamers are sequentially advanced into the intramedullary canal of femur720 leaving the last reamer 310 in situ so that the shank 320 of reamer310 extends from the distal femur. A boss reamer 372 further reams femur720 over shank 320 of reamer 310 (see FIG. 17D). A distal referencingguide 335 and resection jig 330 are connected to reamer shank 320. Oncevarus-valgus and internal-external rotational alignment is achieved, jig330 is pinned to femur 420 via pins 350 and a bone saw 360 is advancedthrough jig 330 to resect the distal femur and form a distal resectedsurface (see FIG. 17E). Resection jig 330, distal referencing guide 335and reamer 310 are then removed from femur 420.

Thereafter, a 3-in-1 cutting block 250 is connected to valgus adaptor150. In this regard, 3-in-1 cutting block 250 has an adaptor connectionmember at a proximal side thereof that is similar to adaptor connectionmember 112. Valgus adaptor 150 is connected to such adaptor connectionmember as described above with relation to connection member 112. Atrial stem 170 is threaded to valgus adaptor 150. Trial stem 170 andadaptor 150 are inserted into femur 720 until cutting block 250 contactsthe distal resected surface (see FIG. 17F). Thereafter block 250 ispinned via pin 350 and a saw 360 is advanced through resection slots incutting block 250 to perform an anterior skim cut, anterior chamfer cut,and a posterior chamfer cut.

Once femur 720 is resected, femur 720 is prepared for a hinge kneeprosthesis. Femoral trial assembly 14 is assembled by connecting valgusadaptor 150 and stem trial 170 to femoral component 100, as previouslydescribed. In addition, since femur 720 is a 3-cut femur, adaptor trials140 are also connected to femoral component 100. This is achieved byengaging second and third resection slots 124 b-c with correspondingflanges 141 a-b of adaptor trials 140. Femoral trial assembly 14 is thenmounted to the distal femur (see FIG. 17H).

Once tibia 710 is prepared, tibial oncology trial 220 is also assembledby attaching appropriate diaphyseal extensions 227, as necessary, todiaphyseal portion 226 of proximal tibial component 224. In addition,insert 60 is mounted to tray portion 228, bearing component 70 isengaged to axle component 40, and axle boss 50 is inserted into theproximal end of tibial oncology trial 200. Tibial oncology trial 220 isconnected to tibia 710, and femoral trial assembly 14 and tibialoncology trial 220 are connected (see FIG. 17I). In this regard, axle 46is inserted into a bearing recess 115 of femoral component 100 betweencondylar portions 122. Locking shuttle 130 is moved into a posteriorposition to lock axle 46 into place.

Patella tracking and overall joint kinematics is evaluated by rotatingtibial oncology trial 220 relative to femoral trial assembly 14 andabout axle 46. In this particular method, distalizing screws 160 may notbe utilized as the initial resection of the distal femur should besufficient to appropriately align femoral component 100 in aproximal-distal direction relative to the patella when femoral component100 is mounted to the distal femur. In addition, resecting throughfemoral component 100 need not be performed as the appropriateresections are performed with resection jig 330 and 3-in-1 cutting block250 and as femoral augments are likely unnecessary as femur 720 may havebeen pristine prior to the procedure. If necessary, further resectionsmay be performed on tibia 710.

If more distance between assemblies is required, the knee is flexed toabout 90 degrees and tibial insert 60 is removed from tray portion andbearing component 70 is disengaged from a first pair of grooves 56.Threaded wrench 400 is inserted into axle component 40 so as to engageinternal threads 51 (see FIG. 17J). Wrench 400 is turned clockwise whichdistracts tibial oncology trial 220 and femoral trial assembly 14. Thisis performed until bearing component 70 can be engaged to a second pairof grooves 56 and while axle 46 remains disposed within the bearingrecess 115 of femoral component 100. In this regard, bearing component70 is engaged to a second pair of grooves 56 located more distal thanthe first pair of grooves 56 and insert 60 is mounted back onto trayportion 30. Wrench 400 is removed from axle component 40 and bearingcomponent 70 is allowed to once again contact insert 60. At this point,tibial oncology trial 220 is more distant from femoral trial assembly 14than when bearing component 70 was engaged to the first pair of grooves56. Joint kinematics are re-evaluated and the distance betweenassemblies 14 and 220 is adjusted again as necessary. Once theappropriate separation between assemblies 14 and 220 is achieved, theoperator reads indicia 58 through viewing notch 71 which indicates tothe operator the appropriate sized tibial insert for use in the finalhinge knee prosthesis. The assemblies 14 and 220 are then disassembledand the final hinge knee prosthesis is implanted.

FIGS. 18A and 18B illustrate further method embodiments of preparing atibia and femur to receive a hinge knee prosthesis. In a revisionprocedure, bone deformities, such as bone voids, are often found in adistal femur or proximal tibia. Such deformities may make it difficultto obtain bone-to-prosthesis contact when a hinge knee prosthesis isimplanted and may weaken the bone. In this regard, void fillingprostheses, such as cones or sleeves, can be utilized to fill suchdeformities and provide structural support. Examples of such voidfilling prostheses are disclosed in U.S. application Ser. No.14/992,695; U.S. Publication No. 2014/0277567; and U.S. Pat. Nos.9,011,444 and 9,149,282, the disclosures of which are herebyincorporated by reference herein in their entireties.

As shown in FIG. 18A, an alternative tibial trial assembly 12′ includesbaseplate component 20, trial stem 21, and tibial void filling trial900. Also included in trial assembly 12′, but not depicted in FIG. 18A,is tibial insert 60, bearing component 70, keel trial 80 and axlecomponent 90. Tibial void filling trial 900 mimics a tibial void fillingprosthesis and includes a body 902 that has an opening extending throughit in a proximal-distal direction. In addition, in the embodimentdepicted, void filling trial 900 includes a lobe portion 904 connectedto body 902. Lobe portion 904 may help fill lateral or medial voids thatextend beyond the boundaries of body 902 when implanted.

In a method of preparing a tibia utilizing tibial trial assembly 12′, apreviously implanted tibial prosthesis is removed from a tibia 810, anintramedullary canal of tibia 810 is reamed and the proximal tibia iscut, as described in detail above. Further reaming is performed in theproximal tibia using void forming reaming assembles, examples of whichare also described in the heretofore incorporated documents, to form auniform void in locations where bone deformities are present. After suchuniform void is formed, void filling trial 900 is inserted into thevoid. Trial stem 21 and baseplate component 20 are inserted into theopening of void filling trial 900 using an introducer, such asintroducer 390, so that stem 21 extends through void filling prosthesis900 and boss 22 is at least partially disposed within the opening ofvoid filling trial 900. Thereafter, keel punch 390 is punched throughkeel slots 38 and through one or more slots in trial 900, and keel trial80 is coupled to baseplate component 20 so that keel portions 82 atleast partially extend into void filling trial 90 and into bone. Tibialinsert 60, axle component 90, and bearing component 70 are alsoassembled to baseplate component 20. Once tibial trial assembly 12′ isassembled and mounted to tibia 810, trial assembly 12′ is connected tofemoral trial assembly 14, or 14′ as described below, via axle 46 ofaxle component 40. Joint kinematics are then assessed, and adjustments,as necessary, are performed, as previously described.

As shown in FIG. 18B, an alternative femoral trail assembly 14′ includesfemoral component 100, valgus adaptor 150, stem 170, and femoral voidfilling trial 910. Femoral void filling trial 910, as depicted, mimics afemoral void filling prosthesis and includes a central body 914 and legmembers 912 connected to central body 914. An opening 916 extendsthrough body 916 and between leg members 912.

In a method of preparing a femur utilizing femoral trial assembly 14′, apreviously implanted femoral prosthesis is removed from a femur 820 andan intramedullary canal of femur 820 is reamed, as described in detailabove. Further reaming is performed in the distal femur using voidforming reaming assembles, examples of which are described in theheretofore incorporated references, to form a uniform void in locationswhere bone deformities are present. After such uniform void is formed,femoral void filling trial 910 is inserted into the void. Trial stem 170and valgus adaptor 150 are inserted into opening 916 of femoral voidfilling trial 910 so that stem 170 extends through void fillingprosthesis 910 and valgus adaptor 150 is at least partially disposedwithin opening 916 of femoral void filling trial 910. Once femoral trialassembly 14′ is mounted to femur 820, femoral trial assembly 14′ isconnected to tibial trial assembly 12 or 12′ via axle component 40.Joint kinematics are assessed, and adjustments, such as via distalizingscrews 160, are performed, as previously described.

Although hinge knee trial assembly 10 has been described as a trial, itis also contemplated that certain aspects of assembly 10 can beimplemented in a final prosthesis, such as axle 46 and its connection tofemoral component 100. In addition, various alternatives arecontemplated. For example, hinge knee trial assembly 10 may not includebearing plate 70. Instead condylar portions of the femoral component 122may directly contact proximally facing bearing surfaces 64 of insert 60.In such embodiment, tibial inserts, like insert 60, of varying thicknessmay be attached to baseplate component 20 in lieu of bearing plate 70 toadjust the distance between the femoral trial assembly 14 and the tibialtrial assembly while axle 46 is connected to femoral component 100.

Moreover, it was discussed that tibial trial assembly 12 and femoraltrial assembly 14 may be utilized in a revision procedure, tibial trialassembly 12 and femoral oncology trial 200 may be utilized in a femoraloncology procedure, and femoral trial assembly 14 and tibial oncologytrial 220 may be utilized in a tibial oncology procedure. However, it isalso contemplated that femoral oncology trial 200 and tibial oncologytrial 220 may be utilized in the same procedure where both a femur andtibia include cancerous growths.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. A hinge knee system comprising: a tibial assembly having a distalend, a proximal end, and an axle component, the distal end comprising abone facing surface for facing an end of a tibia, the proximal endhaving a proximally facing bearing surface, the axle component extendingfrom the proximal end and having an axle and axle support; and a femoralassembly having a distal femoral component, the distal femoral componenthaving first and second condylar portions and an intercondylar portiondisposed therebetween, the intercondylar portion having a recessconfigured to receive the axle and being defined by one or morecontoured surfaces that are configured to articulate with the axle whenthe axle is received within the recess so that the tibial assembly canbe rotated relative to the femoral assembly about the axle.
 2. Theassembly of claim 1, wherein the tibial assembly includes a baseplatecomponent having a tray portion and a boss extending from the trayportion, and the distal end of the of the tibial assembly includes abone facing surface of the tray portion that is configured to connect toa resected proximal tibia.
 3. The assembly of claim 2, wherein thetibial assembly further includes a modular tibial insert that definesthe proximally facing bearing surface and is received by the trayportion.
 4. The assembly of claim 3, wherein the axle component includesa boss slidingly received within an opening extending into the baseplatecomponent and along the boss thereof.
 5. The assembly of claim 4,wherein the tibial assembly further includes a bearing plate having adistally facing bearing surface, the bearing plate being engageable tothe boss of the axle component at one of a plurality of locations alongits length, the distally facing bearing surface corresponding to theproximally facing bearing surface so as to interface therewith when thebearing plate is engaged to the axle component.
 6. The assembly of claim5, wherein the boss of the axle component includes an array oftransverse grooves disposed along its length at predetermined intervals,and the bearing plate includes first and second bearing portions thateach include a flange configured to engage a respective transversegroove of the boss.
 7. The assembly of claim 4, wherein the axlecomponent defines an opening extending through the boss thereof alongits length, and the baseplate component and axle component includeinternal threads situated along their respective openings so that whenthe boss is received within the opening of the baseplate component, theinternal threads of the boss are disposed adjacent the internal threadsof the proximal tibial component.
 8. The assembly of claim 1, whereinthe femoral assembly includes a shuttle slidingly disposed between thefirst and second condylar portions and adjacent the recess, the shuttlehaving a first position in which the recess is exposed so as to receivethe axle and a second position in which the shuttle covers the recess soas to retain the axle within the recess.
 9. The assembly of claim 8,wherein the shuttle includes flanges extending from opposite sidesthereof, and the first and second condylar portions each define slotsthat slidingly receive respective flanges of the shuttle.
 10. Theassembly of claim 1, wherein the distal femoral component includes aplurality of resection slots extending through the first and secondcondylar portions for resecting a distal femur.
 11. The assembly ofclaim 10, wherein the distal femoral component includes a bone interfacesurface configured to interface with previously resected surfaces of adistal femur.
 12. The assembly of claim 1, wherein the femoral assemblyfurther includes a stem adapter and the intercondylar portion includesan adaptor connection member, the stem adaptor has a stem connectionportion that has a threaded opening for threaded connection to anintramedullary stem and a post that extends from the stem connectionportion, and the adaptor connection member includes a post openingconfigured to receive the post.
 13. The assembly of claim 12, whereinthe stem adaptor includes a locking pawl rotatably connected to the stemadaptor, and the adaptor connection member includes a latch openingdisposed adjacent to the post opening so that when the post is disposedin the post opening the locking pawl engages the latch opening.
 14. Ahinge knee system comprising: a tibial assembly having a baseplatecomponent and an axle component, the baseplate component having anopening extending therein from a proximal end toward a distal endthereof, the axle component having a shaft portion receivable within theopening of the baseplate component and an axle connected to the shaftportion extending in a direction transverse to a longitudinal axis ofthe shaft portion; and a femoral assembly having a distal femoralcomponent, the distal femoral component having condylar portions and anintercondylar portion disposed between the condylar portions, theintercondylar portion having a bearing surface defining a recessconfigured to rotatably receive the axle for articulation therewith. 15.The hinge knee system of claim 14, wherein the axle is rigidly fixed andimmovable relative to the shaft portion of the axle component.
 16. Thehinge knee system of claim 15, wherein the shaft portion is rotatableabout the longitudinal axis thereof when the shaft portion is disposedwithin the opening of the tibial component.
 17. The hinge knee system ofclaim 14, wherein the femoral assembly further includes a shuttle whichis slidable in an anterior-posterior direction such that when theshuttle is in a first position, the recess is covered by the shuttle,and in a second position, the recess is exposed so as to be in acondition to receive the axle.
 18. The hinge knee system of claim 14,wherein the bearing surface is disposed entirely between the condylarportions.
 19. The hinge knee system of claim 14, wherein the distalfemoral component includes a plurality of resection slots extendingthrough the condylar portions for receipt of a bone saw for resecting adistal femur.
 20. The hinge knee system of claim 14, wherein the distalfemoral component includes threaded openings extending through thecondylar portions and the femoral assembly includes a distalizing screwconfigured to threadedly engage the threaded openings.